| 摘要 |
<p>PURPOSE:To provide high detecting accuracy using a small number of photo- interrupters by shifting a photo-interrupters in a direction orthogonal with a sheet feed direction, and detecting the change point of output from the photo- interrupter during the shift for finding the position of the side end of a paper sheet under transfer. CONSTITUTION:A photo-interrupter P12 is stopped, when a screen 7 is detected, and made to stay at a reference point (z). When a control circuit 6 outputs a control signal s2, a stepping motor 4 is driven to move the photo-interrupter P12 to a scan start position (y) at the predetermined distance, according to the size of a sheet to be used via a mechanism 3, and kept in standby state at the position (y). When a paper sheet 1 under transfer passes the scan start position (y) and interrupts the optical path of the photo-interrupter P12 and consequently the output s1 thereof changes, the photo-interrupter P12 is moved to a scan finish position (x). Furthermore, a point for the change of the output s1 during the motion of the photo-interrupter P12 is detected, and a distance from a reference position (z) to the side end of the paper sheet 1 is detected by counting the drive signal pulses of the stepping motor 4.</p> |
